LONDON – Children remain protected against common influenza- and meningitis-causing bacteria for up to 2 years when they were vaccinated using the Hib-MenC-TT (Haemophilus influenzae type b/meningitis C/tetanus toxoid) vaccine in conjunction with one of two conjugate pneumococcal vaccines, according to phase IIIB study results.
More than 80% of children retained antibodies against Neisseria meningitidis serogroup C, and 100% retained antibodies against H. influenzae type b after completion of a full vaccination course.
"This study assessed the long-term persistence of MenC and Hib antibodies approximately 2 years after completion of a full vaccination course with HibMenC-TT, or the control vaccines MenC-CRM197 or MenC-TT, when coadministered with DTPa-containing (or DTPa/Hib-containing) and pneumococcal vaccines," explained study investigator Dr. Ryszard Konior.
Dr. Konior of John Paul II Hospital in Krakow, Poland, reported the findings at the Excellence in Paediatrics annual meeting.
In all, 581 children were evaluated during the study. All received a primary vaccination course at 2, 4, and 6 months of age, a booster vaccination at 11-18 months, and reassessment at 36-40 months.
Children were randomized to one of the following four groups and received various combinations of vaccines for the primary and booster vaccinations:
• Children in the Pn-Men group (n = 144) received a meningitis C conjugate vaccine (MenC-CRM197 [Wyeth’s Meningitec]); a diphtheria, tetanus toxoid, acellular pertussis–hepatitis B virus–polio virus inactivated/H. influenzae type b vaccine (DTPa-HBV-IPV/Hib [GlaxoSmithKline’s Infanrix hexa]); and a pneumococcal conjugate vaccine (nontypeable H. influenzae [NTHi], protein D, diphtheria or tetanus toxoid conjugates) adsorbed (10Pn-PD-DiT [GSK’s Synflorix]) for primary vaccination, followed by MenC-CRM197, a DTPa/Hib-containing vaccine, and 10Pn-PD-DiT for booster vaccination.
• Children in the Pn-Neis group (n = 147) received the same vaccines as did the Pn-Men group, with the exception being the use of MenC-TT (Baxter’s NeisVac-C) in place of MenC-CRM197.
• Children in the Pn-HibC group (n = 149) were given Hib-MenC-TT (GSK’s Menitorix), DTPa-HBV-IPV/Hib, and 10Pn-PD-DiT for primary vaccination and vaccination, followed by Hib-MenC-TT, a DTPa-containing vaccine, and 10Pn-PD-DiT for booster vaccination.
• Children in the Pr-HibC group (n = 141) were given the same vaccines as was the Pn-HibC group, with the exception being that 10Pn-PD-DiT was replaced with a seven valent pneumococcal conjugate vaccine (7vCRM [Pfizer’s Prevnar]).
"More than 82% of subjects retained rSBA [rabbit serum bactericidal antibodies] titers [greater than or equal to] 1:8 at 2 years post booster vaccination," said Dr. Konior, which showed sustained protection against the meningitis-causing bacteria. The percentage of children with antibody titers above this threshold was similar in the Pn-Men, Pn-HibC, and Pr-HibC groups, albeit lower than the percentage in the Pn-Neis group.
In addition, all children had anti-PRP (polyribosylribitol phosphate) greater than or equal to 0.15 mcg/mL, indicating that they remained protected against H. influenzae infection. The best results were achieved in the Pn-HibC group, with the lowest antibody titers observed in the groups with a DTPa/Hib-containing vaccine (that is, Pn-Neis and Pn-Men).
Dr. Konior reported that there were no safety concerns. He concluded that these results suggest that seropositivity and seroprotection against both N. meningitidis serogroup C and H. influenzae type B persists in most children up to 3 years of age or older, and that the results favor the use of Hib-MenC-TT (Menitorix) in conjunction with conjugate pneumococcal vaccines.
GlaxoSmithKline Biologicals in Rixensart, Belgium, supported the study. Dr. Konior has participated in clinical vaccine studies sponsored by GSK, Baxter, Novartis Vaccines, and Wyeth (now part of Pfizer).